Merge commit 'v2.6.27-rc6' into x86/memory-corruption-check
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 1150444..6a2629d 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1228,6 +1228,29 @@
or
memmap=0x10000$0x18690000
+ memory_corruption_check=0/1 [X86]
+ Some BIOSes seem to corrupt the first 64k of
+ memory when doing things like suspend/resume.
+ Setting this option will scan the memory
+ looking for corruption. Enabling this will
+ both detect corruption and prevent the kernel
+ from using the memory being corrupted.
+ However, its intended as a diagnostic tool; if
+ repeatable BIOS-originated corruption always
+ affects the same memory, you can use memmap=
+ to prevent the kernel from using that memory.
+
+ memory_corruption_check_size=size [X86]
+ By default it checks for corruption in the low
+ 64k, making this memory unavailable for normal
+ use. Use this parameter to scan for
+ corruption in more or less memory.
+
+ memory_corruption_check_period=seconds [X86]
+ By default it checks for corruption every 60
+ seconds. Use this parameter to check at some
+ other rate. 0 disables periodic checking.
+
memtest= [KNL,X86] Enable memtest
Format: <integer>
range: 0,4 : pattern number
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index ed92864..7820d44 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1059,6 +1059,36 @@
low memory. Setting this option will put user-space page table
entries in high memory.
+config X86_CHECK_BIOS_CORRUPTION
+ bool "Check for low memory corruption"
+ help
+ Periodically check for memory corruption in low memory, which
+ is suspected to be caused by BIOS. Even when enabled in the
+ configuration, it is disabled at runtime. Enable it by
+ setting "memory_corruption_check=1" on the kernel command
+ line. By default it scans the low 64k of memory every 60
+ seconds; see the memory_corruption_check_size and
+ memory_corruption_check_period parameters in
+ Documentation/kernel-parameters.txt to adjust this.
+
+ When enabled with the default parameters, this option has
+ almost no overhead, as it reserves a relatively small amount
+ of memory and scans it infrequently. It both detects corruption
+ and prevents it from affecting the running system.
+
+ It is, however, intended as a diagnostic tool; if repeatable
+ BIOS-originated corruption always affects the same memory,
+ you can use memmap= to prevent the kernel from using that
+ memory.
+
+config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
+ bool "Set the default setting of memory_corruption_check"
+ depends on X86_CHECK_BIOS_CORRUPTION
+ default y
+ help
+ Set whether the default state of memory_corruption_check is
+ on or off.
+
config MATH_EMULATION
bool
prompt "Math emulation" if X86_32
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 362d4e7..ec7e56c 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -579,6 +579,157 @@
struct x86_quirks *x86_quirks __initdata = &default_x86_quirks;
/*
+ * Some BIOSes seem to corrupt the low 64k of memory during events
+ * like suspend/resume and unplugging an HDMI cable. Reserve all
+ * remaining free memory in that area and fill it with a distinct
+ * pattern.
+ */
+#ifdef CONFIG_X86_CHECK_BIOS_CORRUPTION
+#define MAX_SCAN_AREAS 8
+
+static int __read_mostly memory_corruption_check = -1;
+
+static unsigned __read_mostly corruption_check_size = 64*1024;
+static unsigned __read_mostly corruption_check_period = 60; /* seconds */
+
+static struct e820entry scan_areas[MAX_SCAN_AREAS];
+static int num_scan_areas;
+
+
+static int set_corruption_check(char *arg)
+{
+ char *end;
+
+ memory_corruption_check = simple_strtol(arg, &end, 10);
+
+ return (*end == 0) ? 0 : -EINVAL;
+}
+early_param("memory_corruption_check", set_corruption_check);
+
+static int set_corruption_check_period(char *arg)
+{
+ char *end;
+
+ corruption_check_period = simple_strtoul(arg, &end, 10);
+
+ return (*end == 0) ? 0 : -EINVAL;
+}
+early_param("memory_corruption_check_period", set_corruption_check_period);
+
+static int set_corruption_check_size(char *arg)
+{
+ char *end;
+ unsigned size;
+
+ size = memparse(arg, &end);
+
+ if (*end == '\0')
+ corruption_check_size = size;
+
+ return (size == corruption_check_size) ? 0 : -EINVAL;
+}
+early_param("memory_corruption_check_size", set_corruption_check_size);
+
+
+static void __init setup_bios_corruption_check(void)
+{
+ u64 addr = PAGE_SIZE; /* assume first page is reserved anyway */
+
+ if (memory_corruption_check == -1) {
+ memory_corruption_check =
+#ifdef CONFIG_X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
+ 1
+#else
+ 0
+#endif
+ ;
+ }
+
+ if (corruption_check_size == 0)
+ memory_corruption_check = 0;
+
+ if (!memory_corruption_check)
+ return;
+
+ corruption_check_size = round_up(corruption_check_size, PAGE_SIZE);
+
+ while(addr < corruption_check_size && num_scan_areas < MAX_SCAN_AREAS) {
+ u64 size;
+ addr = find_e820_area_size(addr, &size, PAGE_SIZE);
+
+ if (addr == 0)
+ break;
+
+ if ((addr + size) > corruption_check_size)
+ size = corruption_check_size - addr;
+
+ if (size == 0)
+ break;
+
+ e820_update_range(addr, size, E820_RAM, E820_RESERVED);
+ scan_areas[num_scan_areas].addr = addr;
+ scan_areas[num_scan_areas].size = size;
+ num_scan_areas++;
+
+ /* Assume we've already mapped this early memory */
+ memset(__va(addr), 0, size);
+
+ addr += size;
+ }
+
+ printk(KERN_INFO "Scanning %d areas for low memory corruption\n",
+ num_scan_areas);
+ update_e820();
+}
+
+static struct timer_list periodic_check_timer;
+
+void check_for_bios_corruption(void)
+{
+ int i;
+ int corruption = 0;
+
+ if (!memory_corruption_check)
+ return;
+
+ for(i = 0; i < num_scan_areas; i++) {
+ unsigned long *addr = __va(scan_areas[i].addr);
+ unsigned long size = scan_areas[i].size;
+
+ for(; size; addr++, size -= sizeof(unsigned long)) {
+ if (!*addr)
+ continue;
+ printk(KERN_ERR "Corrupted low memory at %p (%lx phys) = %08lx\n",
+ addr, __pa(addr), *addr);
+ corruption = 1;
+ *addr = 0;
+ }
+ }
+
+ WARN(corruption, KERN_ERR "Memory corruption detected in low memory\n");
+}
+
+static void periodic_check_for_corruption(unsigned long data)
+{
+ check_for_bios_corruption();
+ mod_timer(&periodic_check_timer, jiffies + corruption_check_period*HZ);
+}
+
+void start_periodic_check_for_corruption(void)
+{
+ if (!memory_corruption_check || corruption_check_period == 0)
+ return;
+
+ printk(KERN_INFO "Scanning for low memory corruption every %d seconds\n",
+ corruption_check_period);
+
+ init_timer(&periodic_check_timer);
+ periodic_check_timer.function = &periodic_check_for_corruption;
+ periodic_check_for_corruption(0);
+}
+#endif
+
+/*
* Determine if we were loaded by an EFI loader. If so, then we have also been
* passed the efi memmap, systab, etc., so we should use these data structures
* for initialization. Note, the efi init code path is determined by the
@@ -750,6 +901,10 @@
high_memory = (void *)__va(max_pfn * PAGE_SIZE - 1) + 1;
#endif
+#ifdef CONFIG_X86_CHECK_BIOS_CORRUPTION
+ setup_bios_corruption_check();
+#endif
+
/* max_pfn_mapped is updated here */
max_low_pfn_mapped = init_memory_mapping(0, max_low_pfn<<PAGE_SHIFT);
max_pfn_mapped = max_low_pfn_mapped;
diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c
index d37f293..657a16a 100644
--- a/arch/x86/mm/init_32.c
+++ b/arch/x86/mm/init_32.c
@@ -907,6 +907,8 @@
int codesize, reservedpages, datasize, initsize;
int tmp;
+ start_periodic_check_for_corruption();
+
#ifdef CONFIG_FLATMEM
BUG_ON(!mem_map);
#endif
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index d3746ef..f4db527 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -769,6 +769,8 @@
{
long codesize, reservedpages, datasize, initsize;
+ start_periodic_check_for_corruption();
+
pci_iommu_alloc();
/* clear_bss() already clear the empty_zero_page */
diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
index 273a944..bf6d355 100644
--- a/drivers/base/power/main.c
+++ b/drivers/base/power/main.c
@@ -254,6 +254,7 @@
static void pm_dev_dbg(struct device *dev, pm_message_t state, char *info)
{
+ check_for_bios_corruption();
dev_dbg(dev, "%s%s%s\n", info, pm_verb(state.event),
((state.event & PM_EVENT_SLEEP) && device_may_wakeup(dev)) ?
", may wakeup" : "");
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 2651f80..50873b2 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -240,6 +240,23 @@
extern void add_taint(unsigned);
extern int root_mountflags;
+#ifdef CONFIG_X86_CHECK_BIOS_CORRUPTION
+/*
+ * This is obviously not a great place for this, but we want to be
+ * able to scatter it around anywhere in the kernel.
+ */
+void check_for_bios_corruption(void);
+void start_periodic_check_for_corruption(void);
+#else
+static inline void check_for_bios_corruption(void)
+{
+}
+
+static inline void start_periodic_check_for_corruption(void)
+{
+}
+#endif
+
/* Values used for system_state */
extern enum system_states {
SYSTEM_BOOTING,